1. Field of the Invention
The invention concerns a turbine shaft more particularly an elastic fluid turbine shaft, having a succession of cylindrical bearings arranged in a stepped configuration and on which are installed disks bearing blades on at least one portion of those cylindrical bearings.
2. Description of the Prior Art
Great concentrations of stresses occur in the shaft at the separation between two successive cylindrical bearings. An attempt has already been made to reduce those stresses by providing a conical clearance in the rings bearing blades so that their fitting surface on the shaft does not come up to the end of the cylindrical bearings of the shaft and by connecting together two successive cylindrical bearings of the shaft by a connecting surface of revolution having a curved profile and a progressively decreasing diameter from the diameter of that of the two successive cylindrical bearings having the greatest diameter, to the diameter of that of the two successive cylindrical bearings having the smallest diameter, but the zone at the beginning of the rounded part of the profile on the bearing having the smallest diameter, which is a zone greatly affected by the alternate bending stresses of the shaft also happens to be subjected to great shrinking stresses; moreover, that connecting surface causes difficulties in machining.
The invention is intended to obviate those disadvantages by means of a connecting surface which can be more easily machined and by spacing apart from one another the zones subjected to the various stresses.